Meaning: The knight's sword was able to cut through the dragon's scales.
Choice of Words: Sharp: Having a keen edge or point.
Meaning: This means that the sword was able to cut things easily and it was not likely to break.
Choice of Words: The knight's sword was sharp and strong.
Meaning: This means that the sword was able to cut things very easily and it was not likely to break at all.
Choice of Words: Very sharp and very strong are used to emphasize how sharp and strong the sword was.
Meaning: This means that the sword was able to cut through anything, no matter how hard or thick it was.
Choice of Words: So sharp and strong, it could cut through anything is used to show how incredibly sharp and strong the sword was.